Cylindrical gas igniters are used to ignite a flammable gas for use in connection with all types of heating appliances. It is well known that the gas igniter must be supported relative to a remote external support structure to be in the proper position for efficient ignition of the gaseous material. To support a gas igniter, a bracket securely fastens an insulator housing of the gas igniter to a support structure in the appliances. The bracket is capable of withstanding the variable environment. Such gas igniters are used to ignite flammable gas, which in turn is used to provide the heat for the heating apparatus or appliances. The support bracket is subjected to high temperatures created by the burning gas. In addition, the gas igniter and bracket are both subjected to intermittent vibrations. It is, therefore, beneficial for the bracket to be rigid and capable of absorbing shock, while maintaining the proper orientation of the heating element of the gas igniter. Due to the adverse conditions in which the igniter and bracket are used, it is common practice to produce the bracket from a thin sheet metal corrosion resistant metal.
A mounting device or bracket for a gas igniter solving the various technical problems associated with a gas igniter is disclosed in U.S. Publication No. 2004/0206856. This type of surrounding bracket has been very successful in practice; however, it is relatively expensive and requires a number of formed sheet metal components and a multitude of assembly operations. Thus, there is a commercial need for a mounting device to be used with a cylindrical gas igniter, which device accomplishes the objectives of the bracket shown in the recent publication, but involves use of less metal, has a lower cost and requires fewer assembly operations.
The invention involves a mounting device for a gas igniter which performs the necessary functions for mounting the gas igniter to an external structure, which igniter requires substantially less sheet metal, is easy to assemble and, therefore, involves substantially less cost without sacrificing its mechanical effectiveness. The invention is integrally forming of the sheet metal mounting bracket with the ceramic support bushing of the heating element so there is no need for assembly of the bracket onto the heating element or bushing, either at the manufacturing facility or in the field, as required by the bracket disclosed in U.S. Publication No. 2004/0206856.
In accordance with the present invention there is provided a gas igniter of the type comprising a heating element including an elongated, high resistance cylindrical nose coil with a central axis and two rear terminal elements electrically insulated from each other. The terminal elements each have a given axial length to thereby define a generally rigid, generally cylindrical support section and an input lead is connected to each of the elements and extends rearwardly from the support section. A bushing is formed from a generally rigid, electrically insulation material and mounts the heating element onto an external support structure. In accordance with the invention the bushing includes a passage with an opened front end for receiving the support section of the heating element with a gap between the support section and the passage. An adhesive mass in the gap secures the heating element into the bushing and a sheet metal mounting bracket is integrally formed with the insulation material of the bushing. Consequently, the bracket extends from the bushing and has a connector portion fixedly attachable to the external support structure. In the preferred embodiment, the adhesive mass integrates the sheet metal bracket with the ceramic bushing. This involves a single adhesive step for securing the heating element to the bushing and the bracket to the bushing. These two mechanical operations can be performed in two steps when the adhesive for mounting the heating element is applied at a different time than the adhesive for integrating the bracket with the ceramic housing. In accordance with the preferred embodiment of the present invention, the passage in the bushing has a cylindrical surface and the bracket has an arcuate portion extending longitudinally from the connector portion of the bracket so the arcuate portion is concentric and coterminous with the cylindrical surface. Indeed, a recess in the surface accommodates the arcuate portion of the mounting bracket.
The ceramic bushing has either a rectangular cross-section with the passage being cylindrical or is a circular cross-section with a cylindrical passage. The insulation material of the bushing is cast ceramic and the adhesive mass is a potting cement. This is standard material for fixing a cylindrical heating element to a ceramic mounting bushing. The bushing has a rear wall closing the element receiving passage with an opening in the rear wall for the input leads connected to the heating element. Furthermore, the front of the bushing has a slot intersecting the passage and, thus, allowing axial sliding insertion of the mounting bracket into the bushing. A single step application of the adhesive mass that integrates or fixedly joins the bushing and mounting bracket.
In accordance with still another aspect of the invention, there is provided a ceramic bushing for supporting a cylindrical heating element of a gas igniter. The bushing includes a cylindrical passage with an open front end for receiving the heating element. The passage has an arcuate recess terminating in a slot extending to the outside of the bushing from the passage. Through this clearance slot a sheet metal bracket is mounted in a given position. The bracket has a connector portion extending through the slot and an arcuate portion laying in the recess in an orientation concentric to the cylindrical passage.
The primary object of the present invention is the provision of a mounting device for a cylindrical heating element of a gas igniter, which mounting device performs the necessary features with a lesser amount of sheet metal in the bracket and requiring fewer mounting operations, so the gas igniter, when assembled, cost less than previous models.
Yet another object of the present invention is the provision of a mounting device, as defined above, which mounting device integrally forms the bracket with the mounting bushing of the gas igniter, so there is no assembly operation in the field and no surrounding bracket assembled to the bushing before shipment.
Still a further object of the present invention is the provision of a mounting device, as defined above, which mounting device involves integrally forming the mounting bracket to the ceramic bushing so there is no assembly operation or possibility of vibration release of the bracket from the bushing.
These and other objects and advantages will become apparent from the description taken together with the accompanying drawings.